Field of the Application
The application generally relates to wireless communications for Cellular Internet of Things (CIoT), and more particularly, to mobile communication devices, Mobility Management Entities (MMEs), and methods for handling changes of CIoT UE usage type.
Description of the Related Art
Cellular Internet of Things (CIoT) is an emerging technology, linking different communication devices, including sensors and actuators, such as Radio Frequency Identifications (RFID), Global Positioning Systems (GPS), and laser scanners, through various wireless technologies, including Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced (LTE-A) technology, and Time-Division LTE (TD-LTE) technology, etc.
Typically, the CIoT technology is used for various purposes related to information collection and analysis, such as monitoring the behavior of persons, things, and/or data through space and time, achieving real-time awareness of the physical environment, assisting human decision making through deep analysis and data visualization, gathering information in diverse settings including natural ecosystems, buildings, and factories and sending the information to one or more server stations. The collected and analyzed information may be used for automation and control, such as automated control of closed systems, control of consumption to optimize resource use across networks, and automated control in an open environment with uncertainty. The emergence of the CIoT technology is promoted by a wide range of applications, including security and surveillance, medical, environmental and weather monitoring, monitoring and control of industrial processes, such as agriculture, smart spaces, and smart cities, among others.
In general, a CIoT User Equipment (UE) may send its usage type to the service network when it is not yet registered with the service network in its current area. Based on the UE usage type and operator policy, the service network may decide which Dedicated Core Network (DCN) the CIoT UE should be redirected to. The basic idea is to separate the data traffic of CIoT UEs from the data traffic of normal UEs, and allow the data traffic to be handled by different core networks. FIG. 1 is a schematic diagram illustrating an exemplary core network selection based on the LTE technology.
However, in the conventional design in compliance with the 3rd Generation Partnership Project (3GPP) specification TR 23.720, a UE (e.g., a CIoT UE or a normal UE) can only send its usage type to the service network when it is not registered in the current area. That is, once the UE has completed registration, it cannot request a change of its usage type to the service network again in the same area. Thus, it is desirable to have a solution for a UE to initiate a change of its usage type even when it has already completed registration in the current area.